Based on your request, it seems you are referring to the celebrated 2003 fantasy-drama film (known in Spanish-speaking regions as El gran pez

The film’s climax is devastatingly quiet. When the fisherman finally confronts the ghost of the fish, he doesn’t harpoon it. Instead, he lets himself be swallowed by it, merging with his own memory in a poignant surrender. The final shot reveals an empty chair by the sea, suggesting that the fisherman has become the very story he once told.